## page was renamed from Diagonalize the DRMI Length Control
== Diagonalize the DRMI Length Control ==

This procedure describes how to measure and invert the input matrix for the 3x3 plant in the DRMI.  This is necessary to prevent cross-coupling between the 3 control loops.  

It's necessary to redo this procedure anytime there is fiddling with the Mach Zehnder or the Marconi signal generators that provide our modulation frequencies.
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==== This procedure won't work on a solaris machine ====
==== This should be run while the DRM is locked & aligned ====


In the $SCRIPTS/LSC directory, run
{{{
setDDphases }}}

This will servo the DD phases to zero, so there will be no offset at the operating point.  After that script finishes, run

{{{
senseDRM }}}

This will measure the plant, giving you info along the way and putting the results into some files.  The last line of screen output should give you something like:

{{{
Your command to copy and paste into a terminal is:


tdswrite C1:LSC-ITMTRX_92 -1.1198 \
C1:LSC-ITMTRX_b2 2.8519 \
C1:LSC-ITMTRX_d2 -0.17059 \
C1:LSC-ITMTRX_f2 0.28573 \
C1:LSC-ITMTRX_122 -0.089699 \
C1:LSC-ITMTRX_142 -0.065893 \
C1:LSC-ITMTRX_95 0.30456 \
C1:LSC-ITMTRX_b5 -0.69205 \
C1:LSC-ITMTRX_d5 0.046096 \
C1:LSC-ITMTRX_f5 -0.074476 \
C1:LSC-ITMTRX_125 0.022033 \
C1:LSC-ITMTRX_145 0.0052107 \
C1:LSC-ITMTRX_93 -1.3128 \
C1:LSC-ITMTRX_b3 2.6644 \
C1:LSC-ITMTRX_d3 -1.5412 \
C1:LSC-ITMTRX_f3 -0.82075 \
C1:LSC-ITMTRX_123 -0.49044 \
C1:LSC-ITMTRX_143 0.070841 \
C1:LSC-ITMTRX_33 0 \
C1:LSC-ITMTRX_42 0 \
C1:LSC-ITMTRX_155 0 }}}

You can copy & paste this command into a terminal to load the new input matrix values.